Jamelia may be widely regarded as the best UK R&B singer in years, but - like most interesting artists - she wears her genre lightly. Although her debut album Drama stole its sound and attitude wholesale from the US, Thank You sees the vocalist take bold steps onto new musical ground.

Indeed, Thank You is at its weakest when it is most generic. First single, "Bout", was hardly a promising introduction, its heavy handed, booming production sounding much like Christina Aguilera's "Dirrty", but without the vocal range and the raw charisma. It tries too hard to achieve too little, as does the embarrassing "Bitch", in which Jamelia tries Pink's attitude on for size but finds it doesn't fit at all.

Jamelia is far more comfortable at the poppier end of the R&B spectrum, where her limited but sultry vocal style flourishes. At certain times in the last few months Capital FM could have been renamed "Superstar" FM, but despite its airplay dominance this champagne pop song still sounds fresh and irresistible. Almost as catchy is the frivolous "Cutie", which nods in the direction of Jamaican dancehall with its giddy, drunken rhythm.

But its on the two slowest numbers that Jamelia triumphs. "See It In A Boys Eyes", a collaboration with Coldplay's Chris Martin, is as beguiling as it is unclassifiable. Built on one of Martin's loveliest ever piano riffs, it's a slinky, haunting hymn to understanding the opposite sex. A perfect partner to Prince's "If I Was Your Girlfriend".

And then there's "Thank You", the album's focal point and a blistering put-down to an abusive former partner. In the hands of a white boy guitar band, the song would likely have become a squeal of anger, but Jamelia handles it with a grace and wisdom that belie her youth - "You messed up my dreams, made me strong/ Thank you." It's that rare beast, a true pop classic which will be played for years to come.

Given the success she is now enjoying, it seems likely that Jamelia's confidence and willingness to experiment can only grow. Her third album should be quite something.